Many modern aircraft include a cryogenic converter for supplying and regulating the flow of refrigerant to cool electronic equipment. The cryogenic converter includes a cryogenic refrigerator with a closed loop nitrogen system. It is necessary to periodically purge or scrub the cryogenic converters and recharge them with nitrogen to enable the refrigerator to function effectively. Scrubbing removes moisture and other contaminants having a tendency to enter the closed loop nitrogen system during operation of the electronic equipment.
The most commonly utilized procedure for scrubbing and charging a cryogenic converter requires 87 manual valve operations. Many of these operations are involved in 20 sequential applications of inert gas to the converter; each gas application is followed by an exhaust cycle when the gas is evacuated from the container. The sequential flow of the inert gas into and out of the converter scrubs the converter of contaminating liquid and other materials. After the container has been scrubbed, it is charged by the inert gas to a predetermined pressure which is dependent upon ambient temperature. The complex series of manual operations must be performed on top of a vertical stabilizer during widely diverse weather conditions which contribute to human errors and often result in unsatisfactory servicing of the converter.
In an attempt to automate the manual operations, an extremely expensive device employing electronic logic networks has been developed. This unit is not self-contained, nor is it portable, as it requires a 160 lb. nitrogen cylinder. Since electronic logic is employed, expensive external power cables must be used to drive the electronic networks, as well as solenoid valve actuators. The prior art unit includes power converting devices, complex electrical timing networks, and requires complex calibration test equipment.
It is, accordingly, an object of the present invention to provide a new and improved automatic apparatus for scrubbing a sealed container with an inert gas and for subsequentially charging the scrubbed container with the inert gas.
Another object of the invention is to provide a new and improved, completely self-contained, portable and easily carried apparatus for automatically scrubbing and charging a sealed container.
Another object of the invention is to provide a relatively inexpensive, self-contained and easily carried apparatus for automatically scrubbing contamination and charging each of a plurality of containers in sequence with an inert gas without using any electrical power.